Avalanche Forecast

Issued: Apr 20th, 2014 9:05AM

The alpine rating is moderate, the treeline rating is low, and the below treeline rating is low. Known problems include Loose Wet, Cornices and Deep Persistent Slabs.

jlammers, Avalanche Canada

South Rockies.

This bulletin was issued using very limited field data. Please send your observations to forecaster@avalanche.ca.Check out this video and blog post for more insight into managing spring conditions.

Summary

Confidence

Poor - Due to the number of field observations

Weather Forecast

Monday: A mix of sun and cloud becoming overcast in the afternoon with light flurries / Moderate southerly winds / Freezing level at about 2000mTuesday: Light to moderate wet snowfall at higher elevations / Moderate southerly winds / Freezing levels are uncertain, although some models are indicating up to 2500mWednesday: Mainly overcast skies with light flurries / Moderate southerly winds / Freezing level at about 1800m

Avalanche Summary

Fairly widespread loose wet avalanche activity was reported on Saturday. The avalanche activity occurred in response to solar radiation and warm temperatures.

Snowpack Summary

Note: We have very little recent data to base this summary on. If you're out in the mountains ask other locals about the current conditions and spend some time making snow and weather observations to help assess local hazard. Prior to the weekend the region received up to 40cm of new snow with the snow line hovering between 1500 and 1700 m. This recent snowfall overlies a melt-freeze crust in many areas. My best guess is that stubborn wind slabs exist in high, north facing terrain while warm temperatures and solar radiation have created moist surfaces everywhere else. If there is a good overnight freeze these surfaces will exist as a hard crust.The deep facet/crust persistent weakness buried at the beginning of February (now down up to 80-100+ cm) should stay on your radar, especially on all alpine slopes during sunny periods. Any activity at this interface would be large and destructive. Also, give large sagging cornices a wide berth when traveling on or below corniced ridges.

Problems

Loose Wet

Forecast sunny breaks and warming on Monday will promote pushy loose wet avalanche activity. Watch for increased reactivity in areas where new snow is exposed to solar radiation for the first time.

Avoid exposure to terrain traps where the consequences of a small avalanche could be serious.>Minimize exposure to sun exposed slopes when the solar radiation is strong.>

Aspects: All aspects.

Elevations: All elevations.

Likelihood

Possible - Likely

Expected Size

1 - 3

Cornices

Large cornices loom above many alpine slopes and will become weak with daytime warming. Give cornices a wide berth while traveling on or below ridges.

Cornices become weak with daytime heating, so travel early on exposed slopes.>Extra caution needed around cornices with current conditions.>

Aspects: North, North East, East, South East.

Elevations: Alpine.

Likelihood

Possible

Expected Size

1 - 5

Deep Persistent Slabs

The potential for deep persistent slabs will increase when the sun is shining, temperatures are warm or when rain falls. Minimize exposure to big alpine slopes when things are warming up.

Be aware of the potential for large, deep avalanches due to the presence of buried persistent weak layers.>

Aspects: All aspects.

Elevations: Alpine.

Likelihood

Unlikely

Expected Size

3 - 6

Valid until: Apr 21st, 2014 2:00PM